The present invention relates to the field of security systems and, more particularly, to a security system and related methods for vehicles.
Vehicle security systems are widely used to deter vehicle theft, prevent theft of valuables from a vehicle, deter vandalism, and to protect vehicle owners and occupants. A typical automobile security system, for example, includes a central processor or controller connected to a plurality of vehicle sensors. The sensors, for example, may detect opening of the trunk, hood, doors, windows, and also movement of the vehicle or within the vehicle. Ultrasonic and microwave motion detectors, vibration sensors, sound discriminators, differential pressure sensors, and switches may be used as sensors. In addition, radar sensors may be used to monitor the area proximate the vehicle.
The controller typically operates to give an alarm indication in the event of triggering of a vehicle sensor. The alarm indication may typically be a flashing of the lights and/or the sounding of the vehicle horn or a siren. In addition, the vehicle fuel supply and/or ignition power may be selectively disabled based upon an alarm condition.
A typical security system also includes a receiver associated with the controller that cooperates with one or more remote transmitters typically carried by the user as disclosed, for example, in U.S. Pat. No. 4,383,242 to Sassover et al. and U.S. Pat. No. 5,146,215 to Drori. The remote transmitter may be used to arm and disarm the vehicle security system or provide other remote control features from a predetermined range away from the vehicle. Also related to remote control of a vehicle function U.S. Pat. No. 5,252,966 to Lambropoulous et al. discloses a remote keyless entry system for a vehicle. The keyless entry system permits the user to remotely open the vehicle doors or open the vehicle trunk using a small handheld transmitter.
Unfortunately, the majority of vehicle security systems need to be directly connected by wires to individual vehicle devices, such as the vehicle horn or door switches of the vehicle. In other words, a conventional vehicle security system is hardwired to various vehicle components, typically by splicing into vehicle wiring harnesses or via interposing T-harnesses and connectors. The number of electrical devices in a vehicle has increased so that the size and complexity of wiring harnesses has also increased. For example, the steering wheel may include horn switches, an airbag, turn-signal and headlight switches, wiper controls, cruise control switches, ignition wiring, an emergency flasher switch, and/or radio controls. Likewise, a door of a vehicle, for example, may include window controls, locks, outside mirror switches, and/or door-panel light switches.
In response to the increased wiring complexity and costs, vehicle manufacturers have begun attempts to reduce the amount of wiring within vehicles to reduce weight, reduce wire routing problems, decrease costs, and reduce complications which may arise when troubleshooting the electrical system. For example, some manufacturers have adopted multiplexing schemes to reduce cables to three or four wires and to simplify the exchange of data among the various onboard electronic systems as disclosed, for example, in xe2x80x9cThe Thick and Thin of Car Cablingxe2x80x9d by Thompson appearing in the IEEE Spectrum, February 1996, pp. 42-45.
Implementing multiplexing concepts in vehicles in a cost-effective and reliable manner may not be easy. Successful implementation, for example, may require the development of low or error-free communications in what can be harsh vehicle environments. With multiplexing technology, the various electronic modules or devices may be linked by a single signal wire in a bus also containing a power wire, and one or more ground wires. Digital messages are communicated to all modules over the data communications bus. Each message may have one or more addresses associated with it so that the devices can recognize which messages to ignore and which messages to respond to or read.
The Thompson article describes a number of multiplexed networks for vehicles. In particular, the Grand Cherokee made by Chrysler is described as having five multiplex nodes or controllers: the engine controller, the temperature controller, the airbag controller, the theft alarm, and the overhead console. Other nodes for different vehicles may include a transmission controller, a trip computer, an instrument cluster controller, an antilock braking controller, an active suspension controller, and a body controller for devices in the passenger compartment.
A number of patent references are also directed to digital or multiplex communications networks or circuits, such as may be used in a vehicle. For example, U.S. Pat. No. 4,538,262 Sinniger et al. discloses a multiplex bus system including a master control unit and a plurality of receiver-transmitter units connected thereto. Similarly, U.S. Pat. No. 4,055,772 to Leung discloses a power bus in a vehicle controlled by a low current digitally coded communications system. Other references disclosing various vehicle multiplex control systems include, for example, U.S. Pat. No. 4,760,275 to Sato et al.; U.S. Pat. No. 4,697,092 to Roggendorf et al.; and U.S. Pat. No. 4,792,783 to Burgess et al.
Several standards have been proposed for vehicle multiplex networks including, for example, the Society of Automotive Engineers xe2x80x9cSurface Vehicle Standard, Class B Data Communications Network Interfacexe2x80x9d, SAE J1850, July 1995. Another report by the SAE is the xe2x80x9cSurface Vehicle Information Report, Chrysler Sensor and Control (CSC) Bus Multiplexing Network for Class xe2x80x98Axe2x80x99 Applicationsxe2x80x9d, SAE J2058, July 1990. Many other networks are also being implemented or proposed for communications between vehicle devices and nodes or controllers.
Unfortunately, conventional vehicle security systems for hardwired connection to vehicle devices, such as aftermarket vehicle security systems, are not readily adaptable to a vehicle including a data communications bus. Moreover, a vehicle security system if adapted for a communications bus and devices for one particular model, model year, and manufacturer, may not be compatible with any other models, model years, or manufacturers. Other systems for remote control of vehicle functions may also suffer from such shortcomings.
In view of the foregoing background, it is therefore an object of the present invention to provide a vehicle security system and associated method which is readily adapted or adaptable for installation in a vehicle having a data communications bus.
It is another object of the present invention to provide a security system or other remote control function systems and associated methods for installation in a vehicle having a data communications bus, and wherein the vehicle is one from among a plurality of different vehicles with different device addresses and/or signal protocols for communicating with the vehicle devices.
These and other objects, advantages and features of the present invention are provided by a vehicle security system for a vehicle of a type including a data communications bus connecting a plurality of vehicle devices. In particular, the vehicle security system preferably comprises a vehicle security sensor and associated sensor bus interface means for interfacing the vehicle security sensor to the data communications bus. The vehicle security system also preferably includes an alarm indicator and associated alarm indicator bus interface means for interfacing the alarm indicator to the data communications bus. An alarm controller and associated alarm controller bus interface means are also preferably included. The security system further preferably comprises desired signal enabling means for enabling the alarm controller to operate using a desired set of signals for a desired vehicle from among a plurality of possible sets of signals for different vehicles. Accordingly, the desired signal enabling means permits the alarm controller to communicate with the vehicle security sensor and the alarm indicator via the data communications bus so that the alarm controller is capable of operating the alarm indicator responsive to the vehicle security sensor. The security system is thus advantageously compatible with many different types of vehicle data communications formats or protocols.
The data communications bus may preferably be a multiplexed data bus. Accordingly, the sensor bus interface means, the alarm bus interface means, and the alarm controller bus interface means may each comprise multiplexing means for interfacing with the multiplexed data bus of the vehicle.
The desired signal enabling means may preferably include memory means for storing a plurality of sets of signals for different vehicles, and selecting means for selecting the desired set of signals from the plurality of different sets of signals. In one embodiment, the selecting means may comprise user selecting means for permitting a user to select the desired set of signals. In another embodiment, the selecting means may comprise determining means for determining the desired set of signals based upon signals on the data communications bus.
The memory means may include device address memory means for storing a plurality of different sets of signals representative of different device addresses for different vehicles. Alternatively, or in addition thereto, the memory means may comprise protocol memory means for storing a plurality of different protocols for different vehicles.
In yet another embodiment, the desired signal enabling means may comprise learning means for learning the desired set of signals. For example, the learning means may comprise downloading learning means for learning the desired set of signals from another device or central station. In particular, the security system may interface to a cellular telephone and the desired set of signals may be downloaded or received and stored via the cellular telephone. In another variation, the learning means may comprise bus learning means for learning the desired set of signals based upon signals on the data communications bus. The security system, according to another aspect of the invention, may also interface with an existing vehicle controller or a communications bus node which is operatively connected to the data communications bus.
A method aspect of the invention is for operating a vehicle security system for a vehicle of a type including a data communications bus connecting a plurality of vehicle devices. The method preferably comprises the steps of interfacing an alarm controller to the data communications bus, and enabling the alarm controller to operate using a desired set of digital signals for a desired vehicle from a plurality of sets of signals for different vehicles to thereby permit the alarm controller to communicate with at least one of a vehicle security sensor and an alarm indicator via the data communications bus. Accordingly, the alarm controller is capable of operating the alarm indicator responsive to the vehicle security sensor and via the data communication bus.
The concepts and features of the invention may also be desirably incorporated in a remote control system for a vehicle, such as a vehicle security system, a remote engine starter system, or a remote keyless entry system, for example. The remote control system preferably comprises a remote transmitter and a receiver within the vehicle for receiving a signal from the remote transmitter. A vehicle function controller is provided along with an associated vehicle function controller bus interface means for interfacing the vehicle function controller to the data communications bus. The remote control system also includes desired signal enabling means for causing the vehicle function controller to operate using a desired set of signals for a desired vehicle from a plurality of possible sets of digital signals for different vehicles. Accordingly, the vehicle function controller can communicate with a vehicle device via the data communications bus so that the vehicle function controller is capable of operating the vehicle device responsive to the remote transmitter. Method aspects of this embodiment of the invention are also disclosed.